1. Field of the Invention
The present invention relates to a washing machine, and more particularly, to a method for controlling a driving of a drum-type washing machine and an apparatus thereof.
2. Description of the Conventional Art
Generally, a washing machine is a mechanical apparatus for washing laundry by performing a washing process, a rinse process, and a dewatering process. The washing machine is divided into a pulsator method, an agitation method, a drum method, and etc. according to a washing method. Hereinafter, a general drum type washing machine will be explained with reference to FIG. 1.
FIG. 1 is a sectional view showing a construction of a drum type washing machine in accordance with the conventional art.
As shown, the drum type washing machine comprises a casing 12, a tub 17 arranged in the casing 12, and a drum 15 rotatably arranged in the tub 17.
Hereinafter, a construction of the drum type washing machine according to the conventional art will be explained in more detail.
The casing 12 has a rectangular parallelepiped shape, and an aperture 22 through which laundry is put in/out is formed at a front side of the casing 12. A door 23 for opening and closing the aperture 22 is disposed at a lateral surface of the aperture 22. The tub 17 for accommodating washing water is installed in the casing 12, and a supporting spring 11 and a damper 18 for shock-absorbingly supporting the tub 17 are respectively installed at upper and lower sides of the tub 17.
A spider 13 for rotatably supporting the drum 15 is coupled to a rear side of the tub 17, and a drum driving motor 14 for rotating the drum 15 is integrally coupled to a rear lateral surface of the spider 13.
A water supply pipe and a water supply valve (not shown) for supplying washing water into the tub 17 are installed at an upper portion of the tub 17, and a drain pump 19 for draining washing water through a drain pipe 16 is installed at a lower portion of the tub 17.
A cyclic water pipe 20 for taking out washing water inside the tub 17 and circulating the taken washing water into the upper portion of the tub 17 is installed at one side of the drain pipe 16, and a circulation pump 21 for pumping washing water is installed at the cyclic water pipe 20.
According to this, when laundry is received in the drum 15 and detergent and washing water are supplied thereto, a control unit (not shown) controls the drum driving motor 14 thus to rotate the drum 15 and drives the circulation pump 21 thus to circulate washing water.
Then, when the washing process is completed, the control unit controls the drain pump 19 and the drum driving motor 14 thus to perform a drain process and a dewatering process in turn and supplies washing water into the tub 17 thus to perform a rinse process several times. Herein, the rinse process is performed several times, and whenever the rinse process is performed one time, the drain process and the dewatering process are also performed one time.
When the dewatering process is performed in a state that laundry is arranged with eccentricity in the drum 15, the drum 15, the tub 17, and a supporting component for the drum 15 (not shown) are damaged and forcibly abraded. Accordingly, in order to prevent the damage and forcible abrasion, an amount of eccentricity of the drum 15 has to be detected before the dewatering process and when the amount of eccentricity is less than a preset reference value, the dewatering process has to be performed.
However, in the conventional drum type washing machine, when the dewatering process is completed after the washing process, or when the dewatering process is completed after the rinse process, a rotation speed of the drum is gradually decreased and the drum is stopped. According to this, vibration and noise are generated at a speed section where vibration of the drum 15 is drastically increased (for example, 150˜200 rpm (revolution per minute)).
Also, in the conventional drum type washing machine, an amount of eccentricity of the drum 15 is detected in a state that the drum 15 is rotated with a speed which is a little increased than a rotation speed of the drum 15 at the time of a washing process after the drum 15 is completely stopped after the washing process is performed, so that vibration and noise are generated at a speed section where vibration of the drum 15 is drastically increased (for example, 150˜200 rpm (revolution per minute)).
Besides, in the conventional drum type washing machine, when the detected amount of eccentricity exceeds the preset reference value (a reference value of an amount of eccentricity of the drum), the drum 15 is stopped and then is driven again, which is repeatedly performed several times or a dozen times. According to this, it takes a lot of time to detect an amount of eccentricity of the drum 15 and then to proceed to a next step by making the amount of eccentricity be less than the preset reference value.
Besides, in the drum type washing machine according to the conventional art, an amount of eccentricity of the drum 15 is detected at a low speed and when the detected amount of eccentricity is less than the preset reference value, a rotational speed of the drum 15 is increased. According to this, the amount of eccentricity of the drum is again increased thus to cause vibration and noise.
In addition, in the drum type washing machine according to the conventional art, the time taken to rinse laundry with washing water is less than the time taken to supply washing water in order to rinse laundry, so that much washing water is put into the tub 17 and time for performing the rinse process is increased.
Minute explanations for the drum type washing machine according to the conventional art are also disclosed in U.S. Pat. Nos. 6,615,619 and 6,612,138.